• 责任者：Deng Chao (College of Geography Science ; Nanjing Normal University ; Nanfing 210023 ; China) ; Wang Yongjin
• 刊名：Quaternary Sciences
• 出版年：2013
• 卷期：33(5)
• 关键词：全新世 ; Holocene ; 石笋微层 ; stalagmite microbanding ; 湖北 ; Hubei Province
• 页码：p.945-953
• 图表：5 illus., 1 table, 63 refs.
• 分类号：1400
• issnNo：ISSN1001-7410
• isbnNo：CN11-2708/P

     The Qingtian cave（31°30＇N,110°22＇E; 1630m above sea level）is located at Mt.Shengnongjia,Hubei Province.The terrain is averagely 1500m a.s.l.and generally become lower from SW to NE.The local annual precipitation averagely is between 1500mm and 2000mm,most of which falls between June and September.The relative humidity and temperature in the cave are about 100% and 15.5℃,respectively.One stalagmite（QT40）was collected deep in the cave.This sample is 179mm in height,with a diameter from 65mm to 76mm.The stalagmite is composed of pure calcite deposition,without evident porous on the polished surface.We identified a potential hiatus between the depth of 3mm and 19mm,supported by 230Th dating and annual lamina counting results.So we focused our oxygen isotope analysis on the section below the depth of 19mm.Nine samples for 230Th dating were conducted at the Isotope Laboratory of Geology and Geophysics Department Minnesota University,USA.A total of 445 samples for δ18O measurements were analyzed with on-line automated carbonate preparation system（KIEL CARBONATE DEVICE）linked to Finnigan MAT -253 ratio mass spectrometer at the Isotope Laboratory of College of Geography Science,Nanjing Normal University.A 2-year-resolution δ18O record between 8.8kaB.P.and 7.9kaB.P.was reconstructed on 8 230Th dates,445 stable isotope measurements and 890±14 annual bands.The δ18O time series shifts within a range of 1.4‰ .Our high-resolution δ18O record reveals a striking weak summer event between 8.34-8.10kaB.P.,with a double-plunging structure.This characteristic has been reported previously in cave records from Southern China and Oman,and appears to different from the δ18O record from the Nuanhe cave,Northern China.In comparison with the recent model simulations and δ18O record from Greenland ice cores,it is possible that the ＂8.2ka＂ event can be coupled to changes in the Atlantic Meridional Overturning Circulation triggered by a glacial lake outburst.However,the monsoonal ＂8.2ka＂ event appears to initiate earlier than Greenland temperature,consistent with a decrease in the solar activity.The external forcing may have a prominent impact on the AM evolution during the ＂8.2ka＂ event.